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I have not yet seen the Science paper, but the simple presence of telomerase RNA in all cells should not impact the potential utility (or lack thereof) of telomerase inhibitors as anti-cancer agents. The presence of telomerase RNA could mean that the RNA component plays multiple roles within the cell: it may be important both for telomerase function as well as some other unknown biological function. An inhibitor of telomerase activity would not be expected to affect the RNA alone since a the effects of a telomerase inhibitor would be limited to those cells that produce active telomerase (i.e., cells that produce both the RNA component and protein component, and they functionally interact). In terms of developing an enzyme inhibitor that is medically useful, you only care if a cell is expresing an enzyme activity and the activity is important for the cell. An example of this concept are inhibitors of DNA polymerases, an important class of cancer chemotherapuetics. All cells have DNA polymerases, and when you treat a person with a compound that ultimately results in inhibition of DNA polymerases (ex. methotrexate, 5-fluorouracil, arabinofuranosyl cytosine, etc.), DNA polymerase activity in all cells is affected. However, the viability of the vast majority of cells are unaffected by this inhibition because DNA polymerase activity is not essential for their survival. In the case of rapidly growing tumor cells, however, they are killed because when a cell is dividing it's survival is essential on DNA polymerase activity. |
